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M. T. HALL. DEVICE FOR TRIMMING 'GRINDSTONBS'L No. 538,071. PatentedApiaZS, 1895.

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UNrTED STATES PATENT OEErcE.

MORRIS T. HALL, OF PARKERSBURG, WEST VIRGINIA, ASSIGNOR OF ONE:

FOURTH TO ALBERT S. MADDOX, OF WASHINGTON, DISTRICT OF CO- LUMBIA.

DEVICE FOR TRIMMING GRIND$TONES.

SPECIFICATION forming part of Letters Patent No. 538,071, dated April23, 1895.

A plication filed November 13, 1894. Serial No. 528,650- (No model.)

To all whom it may concern.-

Be it known that I, MORRIS T. HALL, a citizen of the United States, anda residentof Parkersburg, in the county of Wood and State of WestVirginia, have invented a certain new and useful Improvement in Devicesfor Trimming Grindstones, of which the following is a description.

My invention has relation to a device for trimming and cleaninggrindstones, and is intended more particularly for use in connectionwith the truing of emery, corborundum and corundum grinding andpolishing wheels, such as aroused by dentists.

My object is to provide a device of this character which will be cheapto manufacture, and durable and efficient in use.

In the drawings, Figure 1, is a side elevation of my invention; Fig. 2,asectional view thereof, and Fig. 3, is a plan view of a modified form ofmy invention.

Referring to the drawings, 1 indicates a handle, provided with a forkedor bifurcated end 2, adapted to serve as a journal or bearing for aspindle 3. Situated on the spindle 3 is a series of annular independentdisks 4, 4, 4, whose interior diameter exceeds that of the spindle 3upon which they are mounted, thereby causing the spindle to beeccentricto the peripheries or cutting faces of the disks.

In operation the disks 4, 4, 4, are held in contact with the surface ofthe grind wheel to be trimmed and -cleaned, the said grind wheel beingrevolved by power, thereby causing the independent disks to rotatedraggin gly and eccentrically against the wheel to be trimmed or trued,said disks. at the same time cutting and cleaning the surface of thewheel.

Heretofore it has been customary for dentists to discard wheels of thischaracter after they became uneven and worn, but by means of thisinvention the life of the wheel is pro longed.

As is obvious I may use this invention in truing ordinary grindstones.

In Fig. 3, I have shown a modification of my invention, my object beingto provide a device for cleaning and truing the small corborundum stonesused in connection with dental engines, and in which 5 represents a boxor frame, adapted to be secured to a dental cabinet by means of screws 6and eyes 7. The disks 8, 8 are mounted on spindlesQ, 9, journaled in thesides of the box, and when it is desired to true or trim the corborundumstones, they are revolved through the medium of the engine, and held incontact with the disks, causing them to rotate and truing off thecorborundum stones as desired.

Having thus fully described my invention, what I claim, and desire tosecure by Letters Patent, is

The combination of a frame, a spindle mounted therein, and a series ofindependently revoluble annular disks, mounted freely on said spindle,the diameter of their central openings being greater than that of thespindle, whereby the cutting edges of the disks are permitted to assumean eccentric relation to the spindle.

In testimony whereof I hereunto affix my signature in the presence oftwo witnesses.

MORRIS T. HALL.

Witnesses:

SIMMs POWELL, A. G. J ACKSON.

